In laser applications, such as laser enrichment as described in U.S. Pat. No. 3,772,519, efficient laser utilization requires high intensity pulse outputs at high pulse repetition rates. The desire for higher pulse repetition rates at high intensities in a laser amplifier creates not only a need for efficient heat extraction but also the need for a rapid flow of the lasing medium through the amplifying channel.
The intensity of laser radiation in such applications is a function of the amplification or gain in the laser generation equipment which is in turn a function of the length of the active laser amplifying medium in the path of laser radiation. Particularly where precise frequency control is desired as in laser enrichment, the preferred form of laser amplifier has a long active medium wherein the gain is achieved by the length of the path on a single radiation pass, rather than by multiple reflection through the amplifying medium. It is accordingly desired to provide a long amplification channel of active medium without distortion or sag in the channel resulting from the length of the elements defining the channel.